From patchwork Mon Feb 3 07:11:58 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christophe Leroy X-Patchwork-Id: 1232620 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 489zfM0CKJz9s3x for ; Mon, 3 Feb 2020 18:16:59 +1100 (AEDT) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=c-s.fr Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=c-s.fr header.i=@c-s.fr header.a=rsa-sha256 header.s=mail header.b=YLIlJEBL; dkim-atps=neutral Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 489zfL6D9CzDqNk for ; Mon, 3 Feb 2020 18:16:58 +1100 (AEDT) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=c-s.fr (client-ip=93.17.236.30; helo=pegase1.c-s.fr; envelope-from=christophe.leroy@c-s.fr; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=c-s.fr Authentication-Results: lists.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=c-s.fr header.i=@c-s.fr header.a=rsa-sha256 header.s=mail header.b=YLIlJEBL; dkim-atps=neutral Received: from pegase1.c-s.fr (pegase1.c-s.fr [93.17.236.30]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 489zXd51GDzDq5y for ; Mon, 3 Feb 2020 18:12:01 +1100 (AEDT) Received: from localhost (mailhub1-int [192.168.12.234]) by localhost (Postfix) with ESMTP id 489zXV0ZwJz9tyK3; Mon, 3 Feb 2020 08:11:54 +0100 (CET) Authentication-Results: localhost; dkim=pass reason="1024-bit key; insecure key" header.d=c-s.fr header.i=@c-s.fr header.b=YLIlJEBL; dkim-adsp=pass; dkim-atps=neutral X-Virus-Scanned: Debian amavisd-new at c-s.fr Received: from pegase1.c-s.fr ([192.168.12.234]) by localhost (pegase1.c-s.fr [192.168.12.234]) (amavisd-new, port 10024) with ESMTP id il0wKvoJYDtG; Mon, 3 Feb 2020 08:11:54 +0100 (CET) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase1.c-s.fr (Postfix) with ESMTP id 489zXT6XVQz9tyK0; Mon, 3 Feb 2020 08:11:53 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=c-s.fr; s=mail; t=1580713913; bh=FHgn4N4ltdsIlD1Z5OweivJ/s7UtylttunSmicjjwIM=; h=In-Reply-To:References:From:Subject:To:Cc:Date:From; b=YLIlJEBL3oI/trwY4x5U3NcBJHlx9iCBRuPFVW+88kRXJEOwob7AgRz3B0+n2KSqM YSdQ4l5+eCLIj+tUoXjcDJf0Xl3jg1TJxyuNaGS/TwW/zZjcHfL7r9OWkPyLPJfOm+ 757ZAYq/mdkjaZkceRTVSPqfPoCXat3lQj7m62M8= Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 786618B792; Mon, 3 Feb 2020 08:11:58 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id XN44-1NcEM59; Mon, 3 Feb 2020 08:11:58 +0100 (CET) Received: from po14934vm.idsi0.si.c-s.fr (po15451.idsi0.si.c-s.fr [172.25.230.102]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 4A0628B752; Mon, 3 Feb 2020 08:11:58 +0100 (CET) Received: by po14934vm.idsi0.si.c-s.fr (Postfix, from userid 0) id 3943F652AD; Mon, 3 Feb 2020 07:11:58 +0000 (UTC) Message-Id: In-Reply-To: <80ebd9075cd7c8b412c6d5d05f7542f9026642ef.1580713729.git.christophe.leroy@c-s.fr> References: <80ebd9075cd7c8b412c6d5d05f7542f9026642ef.1580713729.git.christophe.leroy@c-s.fr> From: Christophe Leroy Subject: [PATCH v3 3/7] powerpc/mm/ptdump: debugfs handler for W+X checks at runtime To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , ruscur@russell.cc Date: Mon, 3 Feb 2020 07:11:58 +0000 (UTC) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" From: Russell Currey Very rudimentary, just echo 1 > [debugfs]/check_wx_pages and check the kernel log. Useful for testing strict module RWX. Updated the Kconfig entry to reflect this. Also fixed a typo. Signed-off-by: Russell Currey --- v3: no change v2: no change --- arch/powerpc/Kconfig.debug | 6 ++++-- arch/powerpc/mm/ptdump/ptdump.c | 21 ++++++++++++++++++++- 2 files changed, 24 insertions(+), 3 deletions(-) diff --git a/arch/powerpc/Kconfig.debug b/arch/powerpc/Kconfig.debug index 0b063830eea8..e37960ef68c6 100644 --- a/arch/powerpc/Kconfig.debug +++ b/arch/powerpc/Kconfig.debug @@ -370,7 +370,7 @@ config PPC_PTDUMP If you are unsure, say N. config PPC_DEBUG_WX - bool "Warn on W+X mappings at boot" + bool "Warn on W+X mappings at boot & enable manual checks at runtime" depends on PPC_PTDUMP && STRICT_KERNEL_RWX help Generate a warning if any W+X mappings are found at boot. @@ -384,7 +384,9 @@ config PPC_DEBUG_WX of other unfixed kernel bugs easier. There is no runtime or memory usage effect of this option - once the kernel has booted up - it's a one time check. + once the kernel has booted up, it only automatically checks once. + + Enables the "check_wx_pages" debugfs entry for checking at runtime. If in doubt, say "Y". diff --git a/arch/powerpc/mm/ptdump/ptdump.c b/arch/powerpc/mm/ptdump/ptdump.c index 206156255247..a15e19a3b14e 100644 --- a/arch/powerpc/mm/ptdump/ptdump.c +++ b/arch/powerpc/mm/ptdump/ptdump.c @@ -4,7 +4,7 @@ * * This traverses the kernel pagetables and dumps the * information about the used sections of memory to - * /sys/kernel/debug/kernel_pagetables. + * /sys/kernel/debug/kernel_page_tables. * * Derived from the arm64 implementation: * Copyright (c) 2014, The Linux Foundation, Laura Abbott. @@ -413,6 +413,25 @@ void ptdump_check_wx(void) else pr_info("Checked W+X mappings: passed, no W+X pages found\n"); } + +static int check_wx_debugfs_set(void *data, u64 val) +{ + if (val != 1ULL) + return -EINVAL; + + ptdump_check_wx(); + + return 0; +} + +DEFINE_SIMPLE_ATTRIBUTE(check_wx_fops, NULL, check_wx_debugfs_set, "%llu\n"); + +static int ptdump_check_wx_init(void) +{ + return debugfs_create_file("check_wx_pages", 0200, NULL, + NULL, &check_wx_fops) ? 0 : -ENOMEM; +} +device_initcall(ptdump_check_wx_init); #endif static int ptdump_init(void)